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BaBi4Ti4−x(Cu0.5W0.5)xO15 ceramics with Cu2+ and W6+ co-substitution for the B-site Ti4+ were prepared by using the solid-state reaction process. It was desirable that piezoelectric properties of the BaBi4Ti4−x(Cu0.5W0.5)xO15 ceramics could be improved by inducing the larger lattice distortion with the oxygen vacancy defects neutralized and restrained. Results of the X-ray diffraction analysis confirmed that crystal cell parameter c decreased obviously with the increase in the crystal cell parameter a. Curie temperature, resistivity, and piezoelectric properties of the BBT ceramics are improved by the copper and tungsten modification. The maximum value of piezoelectric coefficient (~ 30 pC/N) can be obtained in the BaBi4Ti4−x(Cu0.5W0.5)xO15 ceramics.

Nowadays, finding an efficient way to treatment oil spill and oily wastewater emission has attracted much attention all over the world. In this work, we fabricated a superhydrophobic coating (humic...

Cancer-associated fibroblasts (CAF) represent a functionally heterogeneous population of activated fibroblasts that constitutes a major component of tumor stroma. Although CAFs have been shown to promote tumor growth and mediate resistance to chemotherapy, the mechanisms by which they may contribute to immune suppression within the tumor microenvironment (TME) in lung squamous cell carcinoma (LSCC) remain largely unexplored. Here, we identified a positive correlation between CAF and monocytic myeloid cell abundances in 501 primary LSCCs by mining The Cancer Genome Atlas data sets. We further validated this finding in an independent cohort using imaging mass cytometry and found a significant spatial interaction between CAFs and monocytic myeloid cells in the TME. To delineate the interplay between CAFs and monocytic myeloid cells, we used chemotaxis assays to show that LSCC patient–derived CAFs promoted recruitment of CCR2+ monocytes via CCL2, which could be reversed by CCR2 inhibition. Using a three-dimensional culture system, we found that CAFs polarized monocytes to adopt a myeloid-derived suppressor cell (MDSC) phenotype, characterized by robust suppression of autologous CD8+ T-cell proliferation and IFNγ production. We further demonstrated that inhibiting IDO1 and NADPH oxidases, NOX2 and NOX4, restored CD8+ T-cell proliferation by reducing reactive oxygen species (ROS) generation in CAF-induced MDSCs. Taken together, our study highlights a pivotal role of CAFs in regulating monocyte recruitment and differentiation and demonstrated that CCR2 inhibition and ROS scavenging abrogate the CAF–MDSC axis, illuminating a potential therapeutic path to reversing the CAF-mediated immunosuppressive microenvironment.

Background: It is known that tumors with more infiltrated immune cells have better responses to PD-1/PD-L1 antibody therapy. PGE2 is involved in the regulation of the cancer microenvironment and tumor growth, mainly through the EP4 receptor. Inhibition of the EP4 receptor may increase tumor-killing immune cell infiltration and thus increase the response to PD-1/PD-L1 antibody therapy. Here we reported a potent and selective EP4 receptor antagonist, KF-0210, for the treatment of cancers. Methods: Multiple experiments were conducted to characterize KF-0210 and to evaluate its anti-tumor activities in vitro and in vivo, including receptor binding assay, cAMP release in cultured cells, and in vivo pharmacokinetic and toxicity studies. Syngeneic mouse tumor models were used to evaluate the effect of KF-0210 on immune cell infiltration and tumor growth. Results: In the EP4 receptor binding assay, KF-0210 showed a potent binding to EP4 receptor (IC50=18.6nM). Its binding potency to EP4 receptor was >500 fold higher than to other prostaglandin receptors, including EP1, EP2, EP3, IP, DP1, and FP. PGE2-induced cAMP production was inhibited by KF-0210 in MCF-7 cells (IC50 = 1.06 nM) and in Flpin-293-mEP4 cells (IC50 = 0.915 nM). In human PBMCs, KF-0210 increased LPS-induced TNFα release (IC50 = 4.5 nM) in the presence of PGE2. Oral administration of KF-0210 showed superior plasma exposure in rats and mice compared to E7046, another EP4 antagonist under clinical development. In the CT26 mouse model of colorectal cancer, KF-0210 increased the tumor-killing immune cells in the tumor. Tumor growth was attenuated by 16%, 36%, and 42% respectively when treated with 10mg/kg, 30 mg/kg/, and 150 mg/kg KF-0210. In the combination therapy studies, when animals were treated with KF-0210 or anti-PD-1 antibody alone, tumor growth was attenuated by 68% and 83% respectively. While combination treatment of KF-0210 and PD-1 antibody achieved 95% inhibition of tumor growth (P Conclusion: KF-0210 is a potent and selective EP4 antagonist with a good PK and safety profile. It shows the inhibitory effect on tumor growth in mouse models of colorectal and breast cancers. The combination treatment of KF-0210 and PD-1/PD-L1 antibodies shows a superior therapeutic effect compared to the monotherapy of each treatment. These results support the clinical development of KF-0210 for cancer therapy, especially the combination therapy with PD-1/PD-L1 antibodies. KF-0210 is currently in phase 1 clinical study and the preliminary data showed good safety and PK profile. Citation Format: Yongqi Deng, Yuan Tian, Tao Rong, Xiangdong Gan, Shuai Qin, Yuanqi Zhou, Xiaomei Wang, Yanlin Jia. Discovery of EP4 receptor antagonist KF-0210 for the treatment of cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2330.

The Cu-1Ni-0.9Sn-0.5Ti-0.3Cr alloy was prepared by vacuum induction melting. The hot deformation experiments with the alloy were carried out using the Gleeble-1500 deformation simulation device at 0.001–10 s−1 strain rate, and 500–900 °C deformation temperature. The hot working constitutive equation for the Cu-1Ni-0.9Sn-0.5Ti-0.3Cr alloy was established. The optimal hot processing of the Cu-1Ni-0.9Sn-0.5Ti-0.3Cr alloy is at 725–900 °C and 0.01–0.223 s−1 strain rate, so the alloy can obtain the required defect-free structure and excellent machinability. The alloy microstructure was analyzed using the electron backscatter diffraction, and the main texture of the Cu-1Ni-0.9Sn-0.5Ti-0.3Cr alloy deformed at 800 ℃ is the {011}< 100 > Goss texture, which is replaced by the {011}< 211 > brass texture at 900 °C. Recrystallization is promoted by higher deformation temperature. The recrystallization process provides energy for recrystallization by consuming dislocations, and the geometrically necessary dislocation density decreases with temperature. Transmission electron microscopy of the alloy shows that the precipitates are mainly Cu and NiTi phases. The interface between the two precipitated phases is semi-coherent. The precipitated phase at a semi-coherent interface can produce smaller elastic stress and lower interfacial energy, thus improving the refinement rate. Meanwhile, the Cu and NiTi phases have high toughness, and grain refinement can effectively improve the strength and hardness of the alloy.

Hepatocellular carcinoma (HCC) is a major world public problem in the world, with high morbidity and mortality rates. Circular RNA (circRNA) circ_0073181 has been reported to be related to HCC development. However, the mechanism of circ_0073181 in HCC is far from being addressed. Circ_0073181, microRNA-548p (miR-548p) and protein tyrosine phosphatase receptor type E (PTPRE) level were detected by real-time quantitative PCR (RT-qPCR). Cell proliferation, migration, invasion and apoptosis were detected by Cell Counting Kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine, wound healing, transwell and flow cytometry assay. Protein levels of proliferating cell nuclear antigen, Bcl-2 related X protein (Bax) and PTPRE were examined by western blot assay. The binding relationship between miR-548p and circ_0073181 or PTPRE was predicted by circular RNA interactome and targetScan and then verified by a dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. The biologic role of circ_0073181 on HCC tumor growth was examined by the xenograft tumor model in vivo. Circ_0073181 and PTPRE were upregulated, and miR-548p was decreased in HCC tissues and cells. Furthermore, circ_0073181 knockdown could boost proliferation, migration, invasion and repress apoptosis of HCC cells in vitro. The mechanical analysis suggested that circ_0073181 could regulate PTPRE expression by sponging miR-548p. In addition, circ_0073181 knockdown suppressed cell growth of HCC in vivo. Circ_0073181 silencing could inhibit HCC cell growth and metastasis partly by regulating the miR-548p/ PTPRE axis, providing a promising therapeutic target for the HCC treatment.

The copper–graphite metal matrix composites were prepared by powder metallurgy method using cuprous oxide and graphite as the raw materials. Their microstructure, relative density, hardness, electrical resistivity and the compressive strength of the cuprous oxide–graphite (Cu2O-Gr) composites were studied. This composite when compared with copper–graphite (Cu-Gr) composites using copper powder and graphite demonstrated that the new composite had finer microstructures with increased to the higher compression strength value. The Brinell hardness is about 1.5-1.6 times higher than the original material and the compressive strength increased by 50-100 MPa. The good parameters can be attributed to the redox reaction that occurs at the interface between cuprous oxide and graphite particles, resulting in uniform distribution of the reinforcements in matrix and strong interfacial bonding between the copper matrix and the graphite particles.

Compared to titanium oxide(TiO2), non-equilibrium stoichiometry titanium oxides(TiO2-x) are promising electrode materials because oxygen vacancy changes the electronic interaction near EF. However, the structural configuration of Ti3O5 (α-Ti3O5 and β-Ti3O5) remains considerable controversy. In particular, the electrochemical performance of TiO2-x is entirely unclear. By means of first-principles calculations, we present the results of structure, average open circuit voltage (Voc) and electronic structure of Ti3O5 and Ti2O3, respectively. We find that our predicted Ti3O5(C2/c) monoclinic structure is more stable than α-Ti3O5 and β-Ti3O5 because of the cohesive force between layered-layered structure. We demonstrate that α-Ti3O5 and β-Ti3O5 are dynamically instable due to the vibration of the O and Ti at the low frequency region. Importantly, we firstly predict a novel Ti3O5(C2/c) monoclinic structure. Compared to TiO2, Ti3O5 and Ti2O3 exhibit metallic behavior because Ti-3d and O-2p bands across EF. In particular, the calculated Voc of Ti3O5 (C2/c) monoclinic structure (3.416 V) is much larger than that of the α-Ti3O5 (1.809 V), β-Ti3O5 (1.454 V) and Ti2O3 (2.255 V) due to the two O sub-boundary layers. We believe that our work opens a new opportunity for developing the titanium oxide as application of lithium ion batteries.

Graphene oxide (GO) nanosheets were dispersed into premixed powders (Cu-0.4 wt% Al/35W5Cr) by wet grinding and vacuum freeze-drying process. The 0.3 wt% GO/Al2O3-Cu/35W5Cr and 0.5 wt%GO/Al2O3-Cu/35W5Cr composites, used for electrical contacts, were fabricated by vacuum hot-pressing sintering. The microstructure was analyzed by field emission scanning electron and transmission electron microscopy. In addition, the Raman spectroscopy and X-ray photoelectron spectroscopy were used to investigate the structural changes of GO before and after sintering. The arc erosion behavior was investigated by the JF04C electrical contact testing apparatus. Consequently, the Al2O3 nanoparticles were evenly dispersed in the matrix, causing dislocation tangles. GO was converted to reduced graphene oxide after sintering. A group of carbon atoms combined with Cr forming Cr3C2 in situ during sintering, which enhanced the interface bonding. Compared with the Al2O3-Cu/35W5Cr composite, the tensile strength of the two contact materials containing 0.3 wt% GO and 0.5 wt% GO was increased by 45% and 34%, respectively. Finally, pips and craters were present on the anode and cathode surfaces, respectively. Tungsten has undergone re-sintering during arcing and formed needle-like structures. Compared with Al2O3-Cu/35W5Cr, the GO/Al2O3-Cu35W5Cr composites have better welding resistance. The final mass transfer direction of the two composites was from the cathode to anode.

The direct absorption solar collector (DASCs) with nanofluids can remarkably improve the utilization efficiency of solar energy. However, in the actual applications, the temperature distribution of the receiver is extremely uneven when the concentration of nanofluids is high or the receiver is deep. This makes the temperature of upper layer much higher than that of the lower layer, resulting in much heat loss to the surrounding by convection. Here, we propose a magnetic forced convection nanofluids absorption system, where an external rotating magnetic field is used to change the heat transfer mechanism of working fluids from traditional heat conduction to the thermal convection. It is found that the photothermal conversion efficiency of FeNi/C-EG nanofluids is up to 58.1% in this system, which is 22.7% higher than non-external rotating magnetic field when the nanofluids concentration is 50 ppm. Furthermore, the agglomeration of nanofluids can be effectively reduced by an external rotating magnetic field.

Copper alloys and copper matrix composites have been attracting a lot of attention lately. Their composition design, preparation, and processing directly affect the final performance. In this review, several typical copper alloys, such as Cu-Fe-P, Cu-Ni-Si, and Cu-Cr-Zr are analyzed. The deformation mechanisms, microstructure evolution, and dynamic recrystallization behavior are summarized. In addition, dispersion strengthened copper matrix composites and graphene reinforced copper matrix composites are reviewed.

Despite the high specific capacities, the practical application of transition metal oxides as the lithium ion battery (LIB) anode is hindered by their low cycling stability, severe polarization, low initial coulombic efficiency, etc. Here, we report the synthesis of the NiO/Ni2N nanocomposite thin film by reactive magnetron sputtering with a Ni metal target in an atmosphere of 1 vol.% O2 and 99 vol.% N2. The existence of homogeneously dispersed nano Ni2N phase not only improves charge transfer kinetics, but also contributes to the one-off formation of a stable solid electrolyte interphase (SEI). In comparison with the NiO electrode, the NiO/Ni2N electrode exhibits significantly enhanced cycling stability with retention rate of 98.8% (85.6% for the NiO electrode) after 50 cycles, initial coulombic efficiency of 76.6% (65.0% for the NiO electrode) and rate capability with 515.3 mA·h·g−1 (340.1 mA·h·g−1 for the NiO electrode) at 1.6 A·g−1.

High-performance ternary transition-metal chalcogenides (TMDs) are desired in various application fields. However, developing ternary TMDs with unique performance via an efficient and economical me...

In order to investigate the effects of chromium on the electrical contact properties of the Al2O3-Cu/15W composites, vacuum hot-pressing sintering and internal oxidation methods were employed to fabricate the Al2O3-Cu/15W and Al2O3-Cu/15W5Cr composites. The microstructure was analyzed by scanning and transmission electron microscopy. The electrical contacts testing was performed using the JF04C testing machine at 30 V DC with 10-30 A current. The effects of Cr on the comprehensive properties, arc erosion morphology and welding force of the electrical contacts were investigated. The mass transfer mechanism was discussed. It was demonstrated that the Al2O3 nanoparticles pinned dislocations. The diffraction spots of the Cu matrix and the γ-Al2O3 disclose an orientation relationship of Cu//γ−Al2O3,{020}Cu//{040}γ−Al2O3. A typical arc erosion morphology, such as needle-like and coral structures was formed, which provides significantly enhanced arc erosion resistance of the contact material. Compared with the Al2O3-Cu/15W composite, the Al2O3-Cu/15W5Cr composite has a lower welding force. The two composites present two distinct mass transfer trends before and after 25 A. The final mass transfer direction of the composites is from the cathode to the anode. The Al2O3-Cu/15W5Cr contacts have less mass change under all testing conditions.

We apply the first-principles calculations to investigate the structure, mechanical, and thermodynamic properties of WB12 and TiB12 under high pressure (0–100 GPa). The calculated results show that WB12 and TiB12 are thermodynamically stable at the 0 GPa or high pressure. WB12 is more thermodynamically stable than TiB12. In particular, the calculated Vickers hardness of WB12 and TiB12 at the ground state is 29.9 GPa and 43.2 GPa, respectively, indicating that TiB12 is a potential superhard material. With increasing pressure, the calculated elastic modulus of WB12 and TiB12 increases gradually. The calculated electronic structure shows that the high Vickers hardness and elastic properties of WB12 and TiB12 derive from the 3D network B–B covalent bonds. In addition, the calculated Debye temperature at the ground state is 927 K for WB12 and 1339 K for TiB12, respectively. With increasing pressure, the calculated Debye temperature of WB12 and TiB12 increases gradually. Our work shows that TiB12 not only exhibits high hardness but also shows better thermodynamic properties in comparison with WB12.

It is generally accepted that the crack is appeared when the thermal stress is accumulated which caused by the mismatch of coefficient of thermal expansion, through which oxygen will severely destroy the substrate at high temperature environments. Therefore, the coatings with gradient structure to reduce thermal expansion mismatch should greatly improve their service stability. Here Al Y gradient coating is prepared on γ-TiAl alloy by magnetron sputtering. The results show that the hot corrosion resistance of γ-TiAl alloy could be greatly improved, and the activation energy at (750 °C–950 °C) can be calculated to be 126.88 KJ/mol for the coating. The Al2O3 and Y3Al5O12 (YAG) are the primary phases after hot corrosion, thus providing efficient protection at 750, 850 °C. At 950 °C, the consumption of oxide layers is accelerated due to the increased temperature so that some corrosive elements (such as S and Na) unavoidably invade into the scale. The improvement of hot corrosion resistance primarily owes to the existence of Y preferentially oxidizes Al to form α-Al2O3, and the effect of grain refinement of YAG phases.

The effects of Co on the Cu-Ni-Co-Si alloys' microstructure and mechanical properties were investigated. The Cu-1.5Ni-1.0Co-0.6Si and Cu-1.5Ni-1.5Co-0.6Si alloys with combined aging and 40–80% cold rolling were also investigated. The hardness, electrical conductivity, and microstructure were characterized, complemented by X-ray diffraction analysis and transmission electron microscopy. At 450 °C alloys aging, the aging precipitated phases are β-Ni3Si and Co2Si. Specifically, the orthorhombic (Ni, Co)2Si precipitates were found, which have the same crystal structure as the Ni2Si precipitates. The crystal orientation relationship between the matrix and the precipitates is: [112]Cu//[112]β//[012]p, ( 1 1 ¯ 1 ) Cu// ( 1 1 ¯ 1 ) β//(021)p; [001]Cu//[001]β//[001]p, (220)Cu//(110)β//(100)p. With the increasing Co content, the properties of the alloy were degraded. However, Co can promote the growth of the precipitates and accelerate precipitation during the aging process. After aging at 500 °C for 2 h, the hardness and conductivity of the Cu-1.5Ni-1.0Co-0.6Si alloy with 40% deformation were 250 HV and 43% IACS, respectively.

Nanoscale microstructure designing is playing an important role in improving the performance of electrode materials of an electrochemical battery. The Sn based anode is among the very high-capacity but less-stable materials, and has been used mostly for anode of the Li-ion battery with unsatisfactory performance. In this work, we design a new type of 3D porous graphene and nano-Sn composite (Sn/Void@G) by simple one-step annealing of graphene oxide, polystyrene spheres and stannic chloride for both high performance Li- and Na-ion battery anodes. More importantly, the 3D porous graphene formed tunable micro-nano void as a highly efficient “bumper” to accommodate the large volume expansion of nano-Sn particles. As results, the discharge specific capacity of the Sn/Void@G, anode still remains 45.3% while the charge-discharge current is increased 50 times, and the capacity is more than 400 mAh g−1 after 500 cycles at 5C rate. For Na storage, the integrated anodes deliver the Na storage capacity of 786.1 mAh/g at 0.1C rate and the capacity of more than 340 mAh/g after 800 cycles at 2C rate. The present result on Li and Na ion battery may pave the way to next generation high power and energy density batteries.

Al2O3-Cu/25W5Cr and Al2O3-Cu/35W5Cr composites were fabricated by vacuum hot-pressing sintering and internal oxidation process. The electrical conductivity, relative density and Brinell hardness were measured. The effects of the nano-Al2O3 and tungsten on the Al2O3-Cu/(W, Cr) composites hot deformation were investigated through the isothermal compression tests using the Gleeble-1500D thermo-mechanical simulator ranging from 650 °C to 950 °C and 0.001–10 s−1 strain rate. The deformed microstructure was characterized and analyzed by optical and transmission electron microscopy. The interaction of work hardening, dynamic recovery and dynamic recrystallization was illustrated. It is demonstrated that Cr particles were extruded into strips; W particles underwent a slight deformation during the hot compression. Besides, the higher tungsten content composite had higher flow stress. Nano-Al2O3 particles pinned dislocations and inhibited the dynamic recovery and dynamic recrystallization. In addition, it is still in the stage of sub-crystals formation at 850 °C, 0.01s−1. Consequently, the Al2O3-Cu/35W5Cr composite has typical dynamic recovery characteristic. Hence, Al2O3-Cu/(W, Cr) composites demonstrate outstanding high temperature performance.

High performance copper alloys are widely used in electrical, electronic, aerospace fields welcomed due to their high electrical conductivity and excellent mechanical properties. At present work, we proposed a new class of Cu-Co-Si-Ti alloy by incorporating the multiple alloying elements, resulting in the multiple strengthening during heat treatment. The achievement of solution strengthening, deformation strengthening and dual-nanoprecipitation strengthening leaded to the Cu-Co-Si-Ti alloy with excellent tensile strength (617.9 MPa) and high electrical conductivity (41.7% IACS) by the optimum process of 50% cold rolling and aging at 500 °C for 30 min. EBSD was used to analyze the microstructure and texture evolution during the aging process. Moreover, it was found that the volume fraction of Goss, Brass, copper and S texture had close connections with the mechanical properties. By comparing with the contributions of multiple strengthening mechanisms, dual-nanoprecipitation strengthening contributed quite a lot due to the nanoprecipitation of Co2Si and Cu4Ti.

Due to severe cracking tendency in IC10 single crystal Ni3Al-base alloy jointed by electron beam welding, the solidification crack in the IC10 alloy weldment is detrimental for crucial applications in industry. In this paper, the cracking mechanism in the IC10 alloy joint was investigated, and a perfect joint without any crack is obtained by controlling chemical composition in weld, which microhardness is equivalent to the IC10 alloy and tensile strength is up to 900 MPa reaching 1.5 times of the IC10 alloy. The cracking initiation is derived from the liquid film of low melting point precipitated phase-Ta2C along grain boundary under welding stress during solidification. With chemical composition controlling that a 0.4 mm Inconel718 alloy layer is deposited by electron beam freeform fabrication on the welding path before welding, the finer high melting point NbC phases replacing Ta2C phases is precipitated along grain boundary, and the preferred orientation slender columnar grain containing with a multitude of deformation twins is formed in weld, which can reduce the number and proportion of high angle grain boundary, attributing to the elimination of solidification cracks and the enhancement of tensile strength.

Cu Ni Si alloys have been widely applied in electronic and electrical industries. The precipitation behavior of some of the Cu Ni Si alloys is still not well understood. In this study, the precipitation behavior of the Cu-3.0Ni-0.72Si alloy aged at 600 °C for different times was investigated by transmission electron microscopy, atom probe tomography and phenomenological theory of precipitation crystallography. A new orientation relationship (OR) between the precipitates and the Cu matrix was found in the over-aged condition and a coarsening mechanism of the metastable precipitates was put forward. The two- and three-dimension invariant line theories were successfully applied in interpreting the evolution of the ORs and the morphologies in the Cu/δ-Ni2Si (Cu/δ) system. At the early stage of aging, the fine metastable δ’-(Cu, Ni)2Si precipitates are coherent with the Cu matrix, with a quasi-Bain OR of (110)Cu||(100)δ′ and [001]Cu||[001]δ′, and four pairs of parallel conjugate planes: ( 1 ¯ 1 ¯ 1)Cu||( 3 ¯ 01)δ′, (111)Cu||(301)δ′, ( 1 ¯ 11)Cu||(021)δ′, and (1 1 ¯ 1)Cu||(0 2 ¯ 1)δ’. The precipitates have a δ-Ni2Si structure, with some Ni atoms substituted by Cu atoms. During growth, the core region of the metastable δ’-(Cu,Ni)2Si precipitate transforms into stable δ-Ni2Si, with a quasi-NW OR of ( 1 ¯ 11)Cu||(021)δ and [110]Cu||[100]δ, while a layer of metastable δ’- (Cu, Ni)2Si still exists around the core. With prolonging aging time, the δ-Ni2Si precipitates with the OR of ( 1 ¯ 11)Cu||(021)δ and [110]Cu||[100]δ grow two-dimensionally to form a plate-like shape, while those with the OR of (111)Cu||(301)δ and [ 1 ¯ 10]Cu||[010]δ grow one-dimensionally to form a fiber-like shape.

The Cu-Ni-Si alloy has widely applications in the lead frames and electronics industries due to its high strength and conductivity. In this work, hot deformation behavior of the Cu-1.5Ni-1.1Co-0.6Si and Cu-1.5Ni-1.1Co-0.6Si-0.1Cr alloys were investigated through the isothermal compression tests using the Gleeble-1500D thermo-mechanical simulator operating at the temperature ranging from 500 °C to 900 °C and 0.001–10 s−1 strain rate. The deformed microstructure was characterized by the electron backscatter diffraction (EBSD) and the transmission electron microscopy. The constitutive equations of the alloys were established. According to the microstructure analysis, it can be observed that the grain size of the alloy with Cr was more uniform. In addition, the misorientation angle of 14.19 during recrystallization was significantly lower than 24 after the recrystallization, which means that the migration rate of grain boundaries is slow. The texture of the Cu-Ni-Co-Si alloy at 800 °C is the Goss {011}〈100〉 texture and {001}〈100〉 cubic texture, while the Goss texture at 900 °C is replaced by the {011} 〈112〉brass texture. The effects of Cr on precipitation phases were analyzed, and the precipitated phases were (Ni, Co)2Si, Co2Si. The addition of Cr promoted precipitation and significantly reduced the precipitate size. The addition of Cr can improve the strength and activation energy of the alloy. The activation energy was 569.8 kJ/mol and 639.5 kJ/mol, respectively.

Although HfB12 is a promising surperhard material because of the boron cuboctahedron cage, the Vickers hardness of HfB12 remains controversial. We apply first-principles calculations to investigate the influence of a transition metal on the structural stability, Vickers hardness and thermodynamic properties of HfB12. The Vickers hardness of HfB12 is 39.3 GPa. In particular, the Vickers hardness of TM-doped HfB12, which are novel superhard materials, is larger than 40 GPa. The Vickers hardness of Re-doped HfB12 is up to 47.6 GPa. The improvement of Vickers hardness is that the introduction of an alloying element improves the localized hybridization between B and Hf, and then enhances the bond strength of the B–B covalent bond and the Hf–B bond. In addition, these alloying elements enhance the melting-point and Debye temperature of the HfB12. Therefore, we believe that alloying is an effective method to improve the Vickers hardness and thermodynamic properties of HfB12 superhard material.

A graphene reinforced Cu/CeO2Cr electrical contact material with high strength and electrical conductivity was designed. Graphene oxide (GO) was prepared with modified Hummers' method. Composite powders of GO, ceria nanoparticles, copper and chromium were prepared by freeze-drying. The GO-Cu/0.5CeO230Cr electrical contact material was prepared by spark plasma sintering. Raman and X-ray photoelectron spectroscopy (XPS) characterization results indicated that during the sintering process, the graphene oxide was transformed into reduced graphene oxide (RGO). In addition, SEM and TEM characterization results indicated that the CeO2 nanoparticles were uniformly dispersed in the matrix, which hindered the movement of dislocations and improved the strength of the matrix, and a small amount of carbon atoms combined with Cr to form Cr3C2, enhancing the interface bonding. Compared with Cu/0.5CeO230Cr composites, the electrical conductivity, hardness, tensile strength, and welding resistance of the two composites containing 0.5 wt% and 1.0 wt% GO were both improved and the 0.5GO-Cu/0.5CeO230Cr composites have better welding resistance.